JP2003291520A - Ink jet recording sheet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ink jet recording sheet for forming an image excellent in water resistance. <P>SOLUTION: In the ink jet recording sheet having a support and at least one ink receiving layer, the ink receiving layer contains silica with a particle size distribution (d10/d90) of 0.22 or more and plate-shaped hydrated aluminum oxide. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet recording sheet, and more particularly, to an ink jet recording sheet which is excellent in water resistance of an image, excellent in drying property of ink and has less ink bleeding.

[0002]

2. Description of the Related Art An ink jet recording sheet is usually prepared by coating an ink receiving layer composed of a filler and a binder on a substrate. It is known to add a cationic ink fixing agent or the like to the ink receiving layer for the purpose of improving the image density of the inkjet recording sheet.
It is known that aluminum oxide, which is one of them, has a high addition effect. However, these conventional products have insufficient water resistance, and it is particularly possible to improve water resistance while maintaining a constant image. For example, in order to prevent image bleeding, dimethylamine and epichloromethane are used in the ink receiving layer. Although it has been attempted to incorporate a polymer of hydrin or a polymer of diallylamine as a raw material, sufficient water resistance of an image has not been obtained for outdoor use such as a poster. (For example, see Patent Document 1)
The term "water resistance" as used herein means a property that an image does not bleed out when it is struck by water droplets or when it is immersed in water for a long time, and when rubbed in a wet state, the ink bleeds and the image is damaged. It refers to a property that does not exist.

[0003]

[Patent Document 1] Japanese Unexamined Patent Publication No. 2002-160440

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to provide an ink jet recording sheet which is excellent in image water resistance, drying property and image density and which does not cause ink bleeding due to water droplets or the like.

[0005]

The present inventor has completed the present invention by discovering that the above problems can be solved by the following constitution after earnest research. That is, in an ink jet recording sheet having a substrate and at least one ink receiving layer, the ink receiving layer has silica having a particle size distribution (d10 / d90) of 0.22 or more, and a plate-like hydrated aluminum oxide. An ink jet recording sheet comprising:

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION An ink jet recording sheet according to the present invention has a substrate and at least one ink receiving layer, and the ink receiving layer has a particle size distribution (d10 / d90) of 0.22 or more. It is an inkjet recording sheet containing silica and a plate-shaped hydrated aluminum oxide. The substrate of the present invention is not particularly limited as long as it has a sheet shape. Specifically, plastic film,
Although various materials such as paper and non-woven fabric can be used, among these materials, a plastic film is preferable from the viewpoint of water resistance, and among them, vinyl chloride resin, polyethylene terephthalate (PET), polypropylene, polystyrene, polycarbonate, and other thermoplastic materials. A resin film is suitable. Further, as the base material, it is also possible to use one in which an inorganic powder such as calcium carbonate is internally added, one in which an organic pigment is internally added, and further, various foamed plastics including a microvoid film, It is also possible to use a multi-layered one. Here, the foamed plastic is a crack or a defect formed on the surface or inside of the film,
Alternatively, it refers to a plastic film having fine bubbles and cavities. These bubbles and cavities can be formed by various methods. For example, there is a method of forming a film containing an inorganic powder such as calcium carbonate by foaming a foaming agent. In addition, in the present invention, the method of forming the bubbles and the formation form of the cavities are not particularly limited. The plastic film referred to here may have a single-layer structure or a multi-layer structure, and includes what is called synthetic paper.

Further, the base material may be, if desired, for the purpose of improving the adhesiveness with the ink receiving layer or the like and the leakage property.
One or both surfaces of the base material can be subjected to surface treatment by an oxidation method or an uneven method. Examples of the above-mentioned oxidation method include corona discharge treatment, chromium oxidation treatment, flame treatment, hot air treatment, ozone / ultraviolet treatment, and the like, and the concavo-convex method includes, for example, a sandblast method and a solvent treatment method. These surface treatment methods are appropriately selected according to the type of the base material, but in general, the corona discharge treatment method is preferably used in terms of effects and operability. Also, an easy adhesion treatment can be applied. The thickness of the base material is not particularly limited and can be appropriately selected depending on the application,
Usually, it is 10 to 400 μm, and preferably 50 to 200 μm, for example, when it is used for making a general poster.

Next, in the present invention, the ink receiving layer means a layer provided on a base material and having an ability to absorb ink. Further, in the present invention, at least one ink receiving layer is formed by binding a powder or pigment filler having a relatively large pore volume and a large oil absorption amount with a hydrophilic or lipophilic binder. I have more than one.

In the present invention, it is essential that the ink receiving layer contains silica having a particle size distribution (d10 / d90) of 0.22 or more. The particle size distribution can be measured using a laser diffraction type particle size distribution measuring device. Here, d10 is the maximum particle size when the particles are added in order from the smaller particle size and the cumulative volume is 10% of the total, and d90 is the particle size from the smaller particle size. The maximum particle size is shown when the cumulative volume is 90% of the total volume. Therefore, as d10 / d90 obtained by dividing the value of d10 by the value of d90 is closer to 1, it means that there is less variation in particle diameter. In the present invention, the particle size distribution (d10 / d90) is 0.22 or more. This improves the water resistance of the image. Further, especially when combined with a plate-like hydrated aluminum oxide described later, the water resistance of the image is dramatically improved. The particle size can be measured by a laser diffraction scattering method. Further, the silica preferably has a pore volume of 1.5 to 2.2 ml / g, and when it is in this range, the ink absorbing property of the ink jet recording sheet is improved and the water resistance of the image is further improved. To be Further, although the silica can be produced by various methods, the one produced by the gel method is preferable from the viewpoint of improving the strength of the ink receiving layer. Here, the ink absorptivity means the absorption capacity and the absorption speed, and when they are large, the blurring of the image is small and the drying speed is high. Further, the silica having an oil absorption of 210 ml / 100 g or more is preferable from the viewpoint of improving the ink absorption and increasing the drying speed of the ink. A preferred range of the amount of silica added is 44 to 44, based on the total solid content of the ink receiving layer.
It is 65% by weight, more preferably 53 to 58% by weight. If it is less than 44% by weight, the image water resistance may be poor, and if it exceeds 65% by weight, the layer strength may be insufficient.

Another feature of the present invention is an ink receiving layer.
To contain plate-like hydrated aluminum oxide.
It For hydrated aluminum oxide, plate-like, feather-like, rod-like
There are various forms such as, but in the present invention, it is plate-like
It is mandatory. Among them, the aspect ratio is 2-6
Preferably, the pore volume is 0.3 cm ^Three
/ G or less, actual with a scanning electron microscope (SEM)
The measurable particle size or particle length must be 5 to 50 nm.
And, and the BET specific surface area is 50 to 350 m.^Two/ G
That satisfies at least one physical property value selected from
It is more preferable if there is. In the present invention, this plate-shaped hydration
Luminium oxide is water resistant for images, especially water drops
In the condition that the image does not bleed out even in the state and in the wet state
Improves scratch resistance, absorbs ink,
It is also effective in reducing bleeding. Further improve the image density
It also shows the effect of increasing. The plate-shaped aluminum oxide hydrate
The preferred range for the amount of the additive is the total solid content of the ink receiving layer.
It is more preferably in the range of 2 to 10% by weight with respect to the form.
It is preferably in the range of 3 to 6% by weight. If less than 2% by weight
Image water resistance may be inferior, and if it exceeds 6% by weight, the sheet
There may be a problem that the device itself curls.

In the present invention, a filler other than the above-mentioned silica may be contained within a range that does not impair the effects of the present invention. The filler is not limited to organic or inorganic, and calcium carbonate, talc, clay, diatomaceous earth,
Examples thereof include aluminum hydroxide, polystyrene, polymethacrylate, titanium oxide, calcined kaolin and the like. These fillers can be used alone or in combination of two or more.

In the present invention, a substance suitable as a binder to be added to the ink receiving layer is a polymer, such as polyvinyl alcohol, polyvinyl butyral, gelatin,
Polyvinyl acetal, carboxymethyl cellulose,
Polyvinylpyrrolidone, styrene-acrylic copolymer,
Examples thereof include ethylene-vinyl acetate copolymer, styrene-butadiene rubber, polyurethane resin and acrylic resin. These can be used alone or as a mixture. Of these, the most preferable is silanol-modified polyvinyl alcohol. When this is used in the present invention, the strength of the ink receiving layer is further improved as compared with other binders. Usually, the strength of the layer tends to decrease when a large amount of a filler is contained, but when a silanol-modified polyvinyl alcohol is used, a large amount of a filler can be contained in order to improve the strength of the layer, and in addition to the improvement of water resistance. As a result, the ink absorbency can be further improved. The addition amount of these binders is 20 to 40% by weight, and more preferably 23 to 40% by weight based on the total solid content of the ink receiving layer.
It is in the range of 30% by weight. If it is less than 20% by weight, the strength of the layer may be lowered such as scratch resistance being lowered, and if it exceeds 40% by weight, the ink absorbency may be insufficient.
The ratio of silica and binder added as the filler is preferably in the range of 1.0 to 2.5 as silica / binder.

Further, the total solid weight of the ink receiving layer is
It is preferably in the range of 5 to 30 g / m ² . 5 g /
If it is less than m ² , image bleeding is likely to occur, and 30 g / m
^If it exceeds ² , the strength of the layer becomes poor. The thickness of the ink receiving layer is such that when the ink receiving layer is one layer, the total thickness of the ink receiving layer is 20 to 20 when there are a plurality of ink receiving layers. The range of 50 μm is preferable, and the range of 30 to 40 μm is particularly preferable. If the thickness of the ink receiving layer is less than 20 μm, the ink absorption may be insufficient, and the image may be blurred and blurred.
When the thickness of the ink receiving layer exceeds 50 μm, the strength of the layer may be lowered and the image density may be lowered. If necessary, a defoaming agent, an antistatic agent, an ultraviolet absorber, a fluorescent whitening agent, a preservative, a pigment dispersant, and a thickener can be mixed in the ink receiving layer.

In the present invention, it is preferable that the ink receiving layer further contains a water-soluble cationic substance. As the water-soluble cationic substance, various substances may be used, but at least one selected from basic aluminum lactate, dicyandiamide condensate, polyallylamine, and a copolymer of diallylamine and allylamine is contained. However, it is preferable from the viewpoint of further improving the image density. Among these, basic aluminum lactate, polyallylamine, and copolymers of diallylamine and allylamine improve the image density and, in spite of being water-soluble cations, do not reduce the water resistance of the ink receiving layer. And is particularly preferable. Furthermore, as a water-soluble cationic substance contained in the ink receiving layer,
By adding polydiallylamine together with at least one selected from basic aluminum lactate, a dicyandiamide condensate, polyallylamine, and a copolymer of diallylamine and allylamine, the light resistance of an image can be improved. The ratio of the polydiallylamine to the cationic substance is preferably such that the weight ratio of the former to the latter is in the range of 1: 9 to 9: 1, and the form of the water-soluble salt is easy to handle. From the viewpoint of the above effects, it is preferable that these water-soluble cationic substances are contained in an amount of 5 to 15% by weight based on the total weight of solid components in the ink receiving layer.

In the present invention, in addition to the ink receiving layer,
Layers having other functions can be provided, and the structures of these layers are not limited at all. That is, an anchor coat layer, an ultraviolet absorbing layer, etc. may be provided in addition to the ink receiving layer. In particular, since the anchor coat layer has an effect of enhancing the adhesiveness between the base material and the ink receiving layer, it is preferably formed between the base material and the ink receiving layer.

For forming the ink receiving layer and other layers, various conventionally known methods such as coating, spraying, dipping and the like can be used. In particular, reverse roll coating, air knife coating, gravure coating, blade coating and the like are preferable. For example, in the case of an ink receiving layer coating liquid, the solid content concentration of the coating liquid is 10 to 20% by weight, and the viscosity is 2 × 10 ^{−1 to} 5 × 10 ⁻¹ Pa · s. Can be engineered. In addition, various conventionally used additives such as a surfactant, a lubricant, a stabilizer, and a coloring agent can be added to the coating liquid. In addition, a desired ink receiving layer is formed by performing a drying process after coating and the like.
100 to 120 ° C. by a usual method such as hot air drying
It is desirable to carry out at a moderate temperature.

[0017]

EXAMPLES Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples. The particle size distribution of silica d10 / d90
HALD Shimadzu laser diffraction particle size analyzer SALD
Measured at -2000A. The evaluation was performed by using a commercially available inkjet printer (Seiko Epson Corporation) on the inkjet recording sheet produced according to each Example and Comparative Example.
MC9000) manufactured by Mfg. Co., Ltd. was used to print with a commercially available pigment type ink, and various evaluations were carried out by the methods described below. (1) Image Water Resistance Cyan (C), magenta (M), yellow (Y), black (K), light cyan (LC) and light magenta (LM) are applied to ink jet recording sheets prepared according to the respective examples and comparative examples. ) Was used to print a JIS high definition color digital standard image N3A. Five minutes after the completion of printing, one drop of distilled water was dropped in the printing section with a dropper, and the degree of outflow of the ink when the distilled water was completely absorbed was visually evaluated. The evaluation was performed according to the following criteria. ◎: No spill ○ ： Slightly spilled, but practically unaffected △ ： Spilled, practically unsatisfactory × ： Many spilled, practically unsuccessful

(2) Drying property Printing was carried out in the same manner as described in (1) Evaluation of water resistance of image, and immediately after that, PPC paper (paper for
Indirect electrostatic process) was applied, and a roller having a width of 4 cm and a weight of 2 kg was reciprocated on the roller twice to apply pressure, and the degree of image transfer was visually observed. ⊚: No transfer ○ ∙ Transfer occurred slightly, but there was no problem in practical use △ ∙ Transfer occurred and there was a problem in practical use × ∙ Many transfer occurred and there was a problem in practical use

(3) Image Density Black prepared by mixing cyan (C), magenta (M), yellow (Y), and black (K) is printed, and the reflection density of the printing area is measured by the Macbeth densitometer RD. It was measured using -918. (4) Bleeding prevention property Cyan (C) and yellow (Y) were continuously printed for solid printing. The degree of ink bleeding at the boundary was visually observed. ◎: No bleeding ○ ： Slight bleeding occurred, but there was no problem in practical use △ ： Bleeding occurred and there was practical problem × ×: Many bleeding occurred and there was practical problem

Example 1 Coating liquid A for ink receiving layer having the composition shown in Table 1 and Coating liquid B for anchor coating layer having the composition shown in Table 2
Was prepared, and the coating solution B was applied to one surface of a polypropylene film having a thickness of 80 μm [“YUPO FPG # 80” manufactured by YUPO Corporation] so that the coating thickness after drying would be 5 μm. After the liquid B was dried, the coating liquid A was applied thereon so as to have a coating thickness of 35 μm and dried to prepare an inkjet recording sheet, and the above evaluation was carried out. The evaluation results are shown in Table 3.

[0021]

[Table 1] * 1 Particle size distribution (d10 / d90); 0.27, pore volume; 2.05 ml / g * 2 Particle diameter 20 to 30 nm, pore volume 0.1 cm ³ /
g, BET surface area 100 to 300 m ² / g * 3 silanol modified

[0022]

[Table 2] * 4 Aragonite type calcium carbonate

Example 2 A coating liquid A was prepared in the same manner as in Example 1 except that the basic aluminum lactate was removed from the coating liquid A of Example 1 to prepare an ink jet recording sheet. The evaluation results are shown in Table 3.

Example 3 A coating liquid A was prepared in the same manner as in Example 1 except that the dicyandiamide condensate was removed from the coating liquid A of Example 1 to prepare an ink jet recording sheet. The evaluation results are shown in Table 3.

Example 4 Instead of the silica used in Example 1, Mizusawa Chemical Industry's "Mizushiru P-78A" (particle size distribution (d10 / d9
0); 0.39, pore volume; 1.60 ml / g) except that the coating liquid A was prepared in the same manner as in Example 1 to prepare an inkjet recording sheet. The evaluation results are shown in Table 3.

Example 5 Instead of the dicyandiamide condensate used in Example 2,
A mixed aqueous solution of a polydiallylamine salt and a polyallylamine salt (manufactured by Nichika Kagaku, trade name: Neofix RX-10
Coating liquid A was prepared in the same manner as in Example 2 except that 18.4 parts by weight (0, solid content concentration 19% by weight) was used to prepare an inkjet recording sheet. The evaluation results are shown in Table 3.

Example 6 Instead of the dicyandiamide condensate used in Example 2,
Same as Example 2 except that 8.8 parts by weight of an aqueous solution of a 1/1 copolymer salt of diallylamine and allylamine (manufactured by Nitto Boseki, trade name: PAA-D11-HCL, solid content concentration 40% by weight) was used. The coating liquid A was prepared to prepare an inkjet recording sheet. The evaluation results are shown in Table 3.

Comparative Example 1 A coating liquid A was prepared in the same manner as in Example 1 except that hydrated aluminum oxide was not used to prepare an ink jet recording sheet. The evaluation results are shown in Table 3.

Comparative Example 2 The same as Example 1 except that the hydrated aluminum oxide used in Example 1 was replaced with "Alumina sol 200" (feather, BET surface area 200 to 400 m ² / g) manufactured by Nissan Chemical Industries. Coating Solution A was prepared to prepare an inkjet recording sheet. The evaluation results are shown in Table 3.

Comparative Example 3 In place of the silica used in Example 1, Mizusawa Chemical Industry's "Mizushiru P-78D" (particle size distribution (d10 / d9
0); 0.20, pore volume; 1.65 ml / g) except that the coating liquid A was prepared in the same manner as in Example 1 to prepare an inkjet recording sheet. The evaluation results are shown in Table 3.

[0031]

[Table 3]

[0032]

[Table 4]

[0033]

The particle size distribution (d) of the ink receiving layer of the present invention is
The inkjet recording sheet containing silica having a 10 / d90) of 0.22 or more and a plate-like hydrated aluminum oxide is excellent in image water resistance, drying property and image density, and bleeding is prevented. This effect is particularly great for ink jet recording inks that use dyes or pigments, and is very useful for ink jet recorded matter for applications requiring water resistance and long-term storage.

Claims (5)

[Claims] 1. An ink jet recording sheet having a substrate and at least one ink-receiving layer, wherein the ink-receiving layer has silica having a particle size distribution (d10 / d90) of 0.22 or more and plate-like hydration. An ink jet recording sheet comprising an aluminum oxide. 2. The silica has a pore volume of 1.5 to 2.2.
The inkjet recording sheet according to claim 1, wherein the sheet is ml / g. 3. The ink receiving layer further contains a water-soluble cationic substance.
The ink jet recording sheet according to [1]. 4. The water-soluble cationic substance is at least one selected from basic aluminum lactate, a dicyandiamide condensate, a polyallylamine, and a copolymer of diallylamine and allylamine. The ink jet recording sheet according to [1]. 5. The ink jet recording sheet according to claim 1, wherein the ink receiving layer further contains silanol-modified polyvinyl alcohol.